Thermal management systems
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Solution Overview
Problem
Conventional refrigeration systems are heavy and power-intensive, making them unsuitable for mobile applications and precise temperature control of high heat flux, temperature-sensitive loads, as they require large compressors and condensers, which are impractical for size and weight constraints.
Innovation Solution
A thermal management system with a multi-evaporator closed-circuit refrigeration system that includes a vapor compression system and a closed-circuit pumping system, using a compressor-less pumping system and an open-circuit refrigeration system to efficiently manage heat loads without upsizing the compressor, allowing for precise temperature control and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional closed-circuit refrigeration systems are used to handle large amounts of absorbed thermal energy, then the cooling capacity is improved, but the system weight and power consumption increase significantly
Solution Approach 1:
The refrigeration system is divided into multiple independent evaporators (first evaporator, second evaporator, third evaporator) that can operate simultaneously or independently. Each evaporator handles a portion of the thermal load, allowing the system to scale cooling capacity by adding evaporators rather than increasing compressor size, thereby reducing system weight for the same cooling capacity.
Solution Approach 2:
The receiver serves multiple functions: storing refrigerant, acting as a heat exchanger during charging/discharging cycles, and regulating refrigerant flow to different evaporators. The compressor operates in multiple modes (compression, pumping, expansion) to handle different operational requirements. This multi-functionality reduces the need for additional components, lowering overall system weight.
2Productivity
If conventional closed-circuit refrigeration systems are used to handle large amounts of absorbed thermal energy, then the cooling capacity is improved, but the power consumption increases significantly
Solution Approach 1:
The system divides the thermal load across multiple evaporators, allowing the compressor to operate at lower power levels while maintaining high cooling capacity. The compressor alternates between compression mode and pumping/expansion mode, reducing peak power consumption while achieving the same total cooling effect through coordinated operation of multiple evaporators.
Solution Approach 2:
The system employs periodic charging and discharging cycles where the receiver alternates between storing and releasing refrigerant. During discharging, the receiver acts as a heat exchanger providing cooling without compressor operation. This periodic action reduces average power consumption while maintaining required cooling capacity over time.
3Productivity
If the compressor size is increased to handle high heat flux loads, then the cooling capacity is improved, but the system size and weight increase making it impractical for mobile applications
Solution Approach 1:
The system uses multiple evaporators of smaller individual size rather than one large evaporator requiring a large compressor. The segmented approach allows high total cooling capacity with a compact compressor, reducing system volume for mobile applications.
Solution Approach 2:
The system changes the operational parameters of the compressor, using it in multiple modes (compression, pumping, expansion) rather than continuous high-power compression. This allows the compressor to maintain smaller size while achieving high cooling capacity through optimized parameter utilization across different operational phases.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces overall size and weight while maintaining efficient heat extraction from high heat flux components, accurately matching temperature set points, and using less power than conventional systems for a given operation period.
Implementation Method 1
an ejector having a primary inlet that receives refrigerant fluid from the receiver and an outlet that delivers refrigerant fluid to the liquid separator from the outlet of the first evaporator
Implementation Method 2
an expansion valve that is disposed at the first evaporator inlet and that causes an adiabatic flash evaporation of a part of refrigerant received from the receiver
Implementation Method 3
a condenser having a condenser inlet coupled to the compressor outlet and having a condenser outlet coupled to the inlet of the receiver, the condenser configured to condense the compressed refrigerant vapor received from the compressor
Implementation Method 4
The first and second evaporators of the vapor compression closed-circuit system are configured to receive the refrigerant fluid from the receiver and to extract heat from at least one heat load
Implementation Method 5
a pump that receives refrigerant from the receiver and pumps the received refrigerant to the inlet of the third evaporator
Data Source
AI summary
A thermal management system is described. The thermal management system includes a receiver configured to store a refrigerant, the receiver having a receiver inlet and a receiver outlet, a closed-circuit refrigeration system including a vapor compression closed-circuit system that includes the receiver, and a closed-circuit system that includes the receiver, wherein the closed-circuit refrigeration system is configurable to receive refrigerant from the receiver through one or both of the vapor compression closed-circuit system and the closed-circuit system.